1. Field of the Invention
A method and apparatus for mounting a body part on a vehicle body for painting. In particular, a reinforcement member is connected to an exterior skin of the body part to prevent sagging of the body part during manufacture and subsequent use of the vehicle.
2. Description of Related Art
A vehicle body is the shell to which body parts of the vehicle are attached. Portions of the vehicle body that are easily visible after the vehicle is fully assembled include, for example, the A-pillar, the vehicle roof, and the areas surrounding the hood, fenders, doors, and trunk. Body parts typically include exterior vehicle components that are attached to the vehicle body. These body parts, which are non-integral to the body may include, for example, plastic garnishes, bumpers, fenders, grilles, passage doors, and fuel doors.
Traditional body parts may be made of a plastic derivative or of metal. Plastic body parts and metal body parts each have inherent advantages and disadvantages. For example, while the plastic body parts may be formed into many more shapes than the metal body parts, the plastic body parts are not as rigid as metal body parts when a force is applied to them. Plastic body parts, however, are more sensitive to elevated temperatures that can occur both during the vehicle manufacturing process and in customer use, as will be discussed hereinafter. On the other hand, while metal body parts are sturdy, a metal body part typically weighs more than the equivalent plastic body part. As such, the fuel economy may be reduced on a heavier vehicle. Metal body parts also may rust or corrode, thereby detracting from the appearance of the vehicle. Accordingly, a vehicle made of both metal and plastic body parts is desirable for a variety of reasons.
During the manufacture of a vehicle, vehicle bodies and body parts are coated during a series of steps as they are conveyed along a coating line. This coating may be traditional spray painting, electro-static coating, powder coating, or other traditional body coating methods. These coating steps include applying a primer to prepare the respective surfaces of the body and body parts for painting, applying a base coat for adding color to the body and body parts, and applying a clear-coat that functions as a protectant for the body and body parts.
In between these coating steps, the vehicle body and body the parts are passed through bake ovens. In the bake ovens, heated air is directed toward the body and the body parts. The bake ovens ensure that the coatings applied to the body and the body parts are adequately dried.
When the body and the body parts are made of different materials, there are usually separate bake ovens for baking the body and the body parts. The separate bake ovens are usually operated at dissimilar temperatures. Furthermore, the amount of time that the coated body and coated body parts are in the different bake ovens can be altered to affect the amount of heat that is exposed to the coated body and coated body parts. For example, the coated body may be baked by exposure to a high temperature for a short period of time. Alternatively, the coated body part may be baked by exposure to a low temperature for a long period of time.
The body parts and the body that are made of dissimilar materials are separately passed through the bake ovens because of differences in the heat tolerances of the materials that make up the body and body parts. For example, the vehicle body is made of steel, and the body parts are made of some derivative of plastic. The steel vehicle body may be exposed to a much higher temperatures in the bake ovens than the plastic body parts. Unfortunately, there are several unintended consequences of preparing the parts in this separate manner.
Since the vehicle body and the body parts are separately coated and baked, there can be an appearance mismatch between the vehicle body and the body parts. Specifically, because of lot to lot variation in coating ingredients and exposure to different baking conditions, the vehicle body and the body parts can have different appearances due to color and finish differences. The body and body parts may have slightly different color hues after being coated, the amount of sheen of the clear coat may be different, and/or the respective surfaces may have different levels of smoothness. As the body and the body parts are usually assembled so that they border each other, any appearance difference is easily detected and thus, undesirable.
Furthermore, additional labor is required when the vehicle body and the body parts are separately coated. The body parts must first be coated and then later assembled with the vehicle body. As such, to be coated, the body parts are attached to a jig to be fed through the coating line and then removed from the jig after completion of the coating. Then, the body parts are installed on the vehicle body.
Accordingly, it is considered apparent why it is not desirable to separately coat the vehicle body and body parts. However, numerous difficulties are also encountered when the vehicle body and body parts are coated and baked as a single entity. For example, as mentioned hereinbefore, the vehicle bodies are usually made primarily of some form of steel and the body parts can be made of a material different than steel, such as, for example plastic. When the combined body and body parts are coated and baked together, difficulties arise during the baking process.
The body parts, which are made of plastic, are not typically as tolerant of high temperatures as the body that is made of steel. As such, damage can occur to the body parts when the body and body parts are jointly baked at a higher temperature. Primarily, any body part that has a wide horizontal section is especially susceptible to sagging. Sagging is not only an appearance defect, but can also cause misalignment issues. For example, if the body part is located near the vehicle hood and headlight opening, the sagging body part can prevent opening/closure of the hood.
Therefore, there exists a need in the art for a body part that is made from a plastic material and is tolerant of the increased temperatures of a bake oven that is traditionally used for metal vehicle bodies.